UDL is based upon the most widely replicated finding in educational research: students are highly variable in their response to instruction. In virtually every report of research on instruction or intervention, individual differences are not only evident in the results, they are prominent. Rather than treat these individual differences as irrelevant (or even annoying) sources of error variance, UDL treats them as main effects; they are fundamental to understanding and designing effective instruction. Accordingly, to meet the challenge of high standards, the UDL approach eschews “one size fits all” curriculum in favor of flexible designs with customizable options to meet individual needs. Such options are varied and robust enough to optimize instruction for diverse learners—the learners that are found in every classroom.
The research that supports UDL comes from three categories: first, there is the research basis for the general principles of UDL. The three basic principles are derived from modern neuroscience and the cognitive science of learning, but they also are deeply rooted in the foundational work of Lev Vygotsky and Benjamin Bloom, who espoused nearly identical principles for understanding individual differences and the pedagogies required for addressing them. (For example, Vygotsky emphasized what is also a key point of a UDL curriculum—that supports or “scaffolds” are not permanent but rather are gradually removed as an individual becomes an expert learner—the way training wheels are unnecessary once are person has successfully mastered bike-riding.)
Second, there is the research identifying the specific practices that are critical to meeting the challenge of individual differences—research that has been amassed over decades and by many different researchers in many different universities and laboratories.
Third, there is the research on specific applications of UDL—this new area of research is in its early stages but will take a more prominent place as full-scale curricular applications and system-wide implementations are developed. Because the research on which these the UDL guidelines are based would extend this summary unmanageably, we will be providing the research associated with each guideline in a separate document on this website.